Grain Refinement in Plain Carbon Steels

Grain refinement has been successfully employed in aluminum, magnesium, and copper based alloys and cast irons. While there has been some work done on grain refinement in steel, there is still not a significant amount of knowledge to help develop an industrial process. The research documented by this paper attempted to produce grain refinement from selected material powders in 1010 and 1030 steel. Selected powders were placed in a shell core cup with a Type S thermocouple, which was then filled with liquid steel. Cooling curves were recorded and used to determine undercooling. Microscopy of the samples verified the amount of grain refinement attained in each sample. CoAl2O4, NiAl, TiN, and TiO2 produced a significant reduction in undercooling in 1010. It was not possible to determine as-cast grain size in the micrographs of the 1010 samples. CeO2, MgO, and NbC reduced the undercooling for the 1030 samples. While CoAl2O4 did not reduced undercooling, it did produce observable refinement in the 1030 samples.